The desorption or removal of extraneous substances from fabrics is a prevalent industrial process. As used herein, the term “extraneous substance” refers to any substance that becomes attached to or is absorbed by a fabric during the use of the fabric. Extraneous substances can include dirt, industrial lubricants such as oils, grease, coolants, water, glycol, and solvents, as well as particulates. In the dry cleaning industry, extraneous substances can include body oils and liquids, as well as soil stains. As a result, the current art contains a variety of different methods by which these substances are either removed from a fabric so that the fabric can be reused.
The steps that are used to separate extraneous substances from fabrics so that the fabrics can be cleaned or recycled for reuse must be chosen so that the desired results: maximum cleaning and minimum waste generation are achieved. Optimization of cleaning inevitably results in a process that is specific to a particular waste stream; that is, the steps of that process will be dictated by the fabric and the composition of absorbed extraneous substance.
The minimization of waste generation, on the other hand, is dictated by those steps that will result in the cleanest materials. Further, the goal of cleanest fabrics is often associated with the generation of harmful wastes to the environment.
In response to the need for a cleaning process that is simple, effective, and allows the cleaning and recycling of fabrics for reuse, the present inventor developed a process described in U.S. Pat. Nos. 6,230,353 and 6,536,061. Although this process met existing needs, it did not address the growing concern regarding typical dry cleaning fluids, such as perchloroethylene. Because various local, state, and federal agencies consider these dry cleaning fluids to be hazardous wastes, the use of them in a cleaning step necessitates their treatment and/or disposal. Not only is hazardous waste disposal costly, but it imposes significant requirements for careful handling in order to protect the environment. Perchloroethylene is also considered to be a health hazard to those that may become over exposed to its fumes if not properly handled and ventilated.
Furthermore, common dry cleaning fluids oftentimes require the use of single to multiple industrial distillers to accommodate their high distillation points. These types of distillers consume significant energy resources and require careful monitoring.
Although cleaning methods thought to be environmentally friendly alternatives to dry cleaning exist, these methods bring with them additional complications and disadvantages. For example, the use of wet cleaning implicates the environmental regulation of water. Another cleaning method uses liquid carbon dioxide as an alternative to perchloroethylene. However, this method requires the use of specially designed machines capable of handling the high pressure required to sustain liquid carbon dioxide.
Therefore, there remains a need for a method and apparatus for removing extraneous substances from fabrics that is simple, safe, effective, environmentally sound, and energy conserving.